I think that anyone should be able to write a book and publish it (yes, even Stephanie Meyer for first degree grammatical and characterisation crimes against humanity and Dan Brown for just being evil). Criminals are people too, just stupid ones, but they need to make a living or else they will be back in jail living off tax-payers. They just shouldn't be able to make too much of a living.
The Proceeds of Crime Act (in Australia at least) ensures a cap on the amount people can earn and the revenue goes towards re-entry and other community projects for people coming out of prison. All good causes.
This has come up in the news today with David Hicks. This guy didn't do anything wrong, but was just stupid, and was locked up in Guantanamo for years. The courts suddenly decide to freeze the royalites of his memoirs. This is all perfectly legal under the Proceeds of Crime Act but still dubious in this particular case. And the money was going to a family trust, not just him personally. His dad was Father of the Year: he's not going to let his son go crazy.
Celebrity criminals are as old as ... something really really really old.